Follow-up Observations of the Nova V1405 Cas = Nova Cas 2021 = PNV J23244760+6111140: Spectra Changed to He/N-type in One Day
ATel #14478; Kenta Taguchi, Keisuke Isogai, Masaaki Shibata, Yusuke Tampo, Naoto Kojiguchi (Kyoto University), Hiroyuki Maehara (National Astronomical Observatory of Japan)
on 20 Mar 2021; 11:40 UT
Credential Certification: Keisuke Isogai (isogai@kusastro.kyoto-u.ac.jp)
Subjects: Optical, Cataclysmic Variable, Nova, Transient, Variables
We report our further follow-up observations of the nova V1405 Cas = Nova Cas 2021 = PNV J23244760+6111140 (see ATels #14471 and #14472 for our previous reports). We obtained the spectra from 2021-03-19.409 UT to 2021-03-19.417 UT (the 2nd page in the PDF) and from 2021-03-19.823 UT to 2021-03-19.851 UT (the 3rd page in the PDF) using the fiber-fed integral field spectrograph (KOOLS-IFU; Matsubayashi et al. 2019) mounted on the 3.8-m Seimei telescope (Kurita et al. 2020).
Compared to previous spectra taken on 2021-03-18.8 UT (the 1st page in the PDF; details are discussed in ATels #14471 and #14472), the N III 4640 and He II 4686 lines have been (almost) diminished. In contrast, the He I 4026, 4471, 4713, 4922, 5016, and 7281 lines have newly appeared or been more prominent, and He I 5876, 6678, and 7065 lines are still seen well. The above changes are also confirmed by Munari, Valisa, and Dallaporta (ATel #14476). Moreover, we can see Balmer lines having P Cygni profiles. We cannot find any Fe II lines. These spectral features indicate that this nova is likely to be one of He/N-type.
We also performed multicolor photometry on 2021-03-19.83 using the 0.4-m telescope at Kyoto University. The nova was B = 8.383, V = 7.730, Ic = 7.233, and Rc = 7.450 then.
Our Spectra
